This article addresses a problem encountered while attempting to perform adaptations on a Webasto Thermo Top Evo auxiliary heater (Module 18) using Ross-Tech VCDS 18.2.0.3 (x64). Despite successful security access using code 20103, adaptation attempts consistently failed across various channels and values. The issue was replicated on a similar vehicle, suggesting a broader problem. We’ll explore the problem, the attempted solutions, and provide the full vehicle auto-scan generated by VCDS 18.
Understanding the Adaptation Failure with VCDS 18
The user successfully gained security access to Module 18 (Auxiliary Heater) using the correct security access code. However, when attempting to change adaptation values within the module, VCDS 18 returned an “Invalid message length or invalid format” error. Several troubleshooting steps were taken, including:
- Varying Adaptation Channels: Different adaptation channels within Module 18 were selected and tested.
- Adjusting Adaptation Values: Values both above and below the current setting were tried to rule out potential minimum/maximum limitations.
- Testing on Another Vehicle: The same procedure was carried out on a similar van, yielding the same error message.
These attempts indicate the problem may not be isolated to a specific vehicle or a simple input error.
VCDS 18 Error Messages and Security Access
The VCDS 18 software displayed two distinct messages:
- Successful Security Access: This confirms the correct security code was entered, granting access to the module.
- Adaptation Error: The “Invalid message length or invalid format” error, appearing after attempting to change an adaptation value, suggests a communication problem between VCDS 18 and the auxiliary heater control module.
Complete Auto-Scan Data from VCDS 18
The following auto-scan, generated by VCDS 18, provides a comprehensive overview of the vehicle’s modules and their status. While no fault codes were found in any module, including Module 18 (Aux. Heat), this data may offer clues for experienced technicians familiar with VW/Audi diagnostics. The scan includes module part numbers, software versions, coding information, and more. This detailed information is crucial for pinpointing potential incompatibilities or communication issues that might be contributing to the adaptation failure.
[Full Auto-Scan data as provided in the original post]Conclusion: Next Steps for Diagnosing the Issue
The persistent adaptation failure, despite successful security access and a lack of fault codes, points to a more complex problem potentially related to communication protocols or module compatibility with VCDS 18. Further investigation is required. Possible avenues for troubleshooting include consulting Ross-Tech’s technical support, checking for VCDS software updates, and verifying the compatibility of VCDS 18 with the specific auxiliary heater module installed in the vehicle. The provided auto-scan data serves as a valuable resource for further analysis.
